Ben Affleck has already ruled out a run for US Senate, declaring that he won’t be a candidate for the seat formerly held by John Kerry. And who can blame him?

Not his younger brother, Casey
, who called us Tuesday to talk about an animal-rights bill in the Legislature, but couldn’t help himself when we asked about Ben’s Oscar-nominated film “Argo.”

“It’s a lock,” Casey said of the likelihood that “Argo” will win the Academy Award for best picture. “I don’t think [Ben] can be stopped. It’s a great movie, he did a great job directing it, and there’s a lot of good will for him. I think people like him.

It’s true that after scoring big with the Producers Guild of America, the Screen Actors Guild, and at the Golden Globes, “Argo” is shaping up to be the front-runner to win the Academy Award. The younger Affleck acknowledged it seemed like a long shot just a month ago, but “that’s the way these things go.” He also said he thinks it’s “strange” that Ben didn’t get nominated for directing the political thriller. (We might put it differently: He was robbed!)

But Ben’s kid brother called to talk about the Massachusetts Prevention of Farm Animal Cruelty Act, which is pending in the Legislature. A vegetarian and longtime animal-rights activist, he’s penned a letter on behalf of Farm Sanctuary, the ASPCA, and the Massachusetts Society for the Prevention of Cruelty to Animals asking lawmakers to pass the bill prohibiting veal crates, gestation crates, and battery cages, generally used to confine chickens.

“Americans don’t see these things all that often, but if you YouTube them, they’re brutal and immoral,” he said. “I know there are a lot of issues — children shooting children, people without jobs, education, health care — but I think we can address multiple issues at the same time.”

While some people may have a low opinion of politicians, Affleck isn’t one of them.

“I’d be happy to talk to legislators about this. Politicians are pretty smart people capable of considering all sides of an issue,” he said. “Look, if you had a neighbor who was keeping his dog in a teeny tiny space and he couldn’t turn around and was just sitting there and wasting away, you’d call the police and the guy would be charged. Why shouldn’t we treat farm animals with the same respect?”

Affleck, who’s 37, just returned from the Sundance Film Festival, where “Ain’t Them Bodies Saints,” his new independent film costarring Rooney Mara, screened to enthusiastic response.

“It’s an art movie. I don’t care if no one sees it,” he said. “I’m familiar with that experience.”

Next up, if everything goes according to plan, is “Boston Strangler,” a thriller about the search for the murderer who terrorized Boston in the 1960s. He’ll produce and maybe play one of the detectives, and Quincy native (and Emerson grad) ChuckMacLean is writing the script.

“It’s coming along,” said Affleck. “[MacLean] is smart as a whip and writes really fast. He loves the case and has read all the books. We hope to [be under way] by the end of the year.”